Small house

[Lightman]

Hi I believe this is my first post!
I have been here a while lurking in the background absorbing all the great information that is posted here.
I don't usually do any architectural work but had some free time and a client asked if they could see a sample of some architectural renders so I got some plans from a builders website and did this scene.
Modeled in LW with the help of LWcad and rendered with path tracing.
I thinks I could of used some more rays to reduce the noise a bit more but rendering times were going up fast
I tried first to render this in LW but could not get rid of the splotchies. I really like the sunsky plugin for LW as it gave the image a really nice warm feeling, but it's not usable in Kray as it's to noisy, so I had to use the Kray sky which I don't really like but it did render without the noise.
I'm really looking forward to K3 and a better sky model.
Thanks for looking
Keith

[Janusz Biela]

Hello!
You did hundreds times better then me in the beginning... I am very critic for renders (especially, ultimately for my self) so really congratulations!

Please notice that, Path Tracing is not "magic" Global Illumination solution!
Shortly, Path Tracing has no interpolations as you know each rays calculated from camera to source of light (yes in this direction) need to be separately calculated. Because is no interpolation in this system also doesn`t exist GI resolution and this means...incredible huge amount of data to calculate. Noise is the effect of no calculated regions.

The question is now: why some surfaces is clean and some are very noisy. Path Tracing is very "sensitive" for amount of bounce lights (recurse).
Then more bounce the more calculations and more noise.
People doesn't understand it and think, Maxwell, Octane, Arnold are quite fast but NO. There is no "fast" in Path Tracing solution. So the second question why sometimes is fast?! This effect comes from small amount of bounces is some situations.
For example having exterior in most situations Path Tracing photos just DIE after one or two bounces by flying to "space" so they are calculated just with one, two or three bounces. Situation DRAMATICALLY change in complex scenes (interiors) when photon must really travel from corner to corner with many bounces.
Why people should not believe in magic fast Path Tracing Render Engines because this is impossible. So seeing HDRi studio in these software with one light source you see nothing
Speed of Path Tracing very strongly depends also from amount of light sources: then more the longer times render and more noisy.

There is no differences between Path Tracing , QMC and Photon Mapping (the same GI mathematical formula , you can find this on Wiki). Differences are in method of shooting photons and calculated GI samples (Final Gathering). Of course Path Tracing accuracy is ultimate and there is nothing to compare but lately distance between Photon Mapping and Path Tracing starting be very small. K3 will have first Photon Map Engine Render which can compete with Path Tracing. This means: over 15-30 times faster render then PT without noise with very similar quality.

First test of K3 are very promising,shooting photons ultra fast ,position of photons incredible accurate - this give us really happiness after over 3 years of codding...even G. is surprise by smoothing rendering in K3 and how extreme amount of photons we can shoot (my record is 10.000.000 photons under one minute with resolution 5 mm and high blur when for K2 this task takes 10-15 min).

To help in Kray with PT you can reduce amount of bounce lights up to four by command:

Code: Select all

recurse 4

and I suggest keep windows glasses with one polygon layer.

and in sampling tab use FG min/max rays 500/0 or better quality 1000/0 (this is static function because in K2 doesn't exist progressive render in PT)

To prove, PT do not need photons you can setup in Photon Tab zero photons.

Path Tracing is recommended for extreme size exterior scenes.

[Keraressi Abdelkarim]

try unchaced in kray preset ^^ . u will get really nice result without noise .and put in rays min and max liuke 800/1600. or 900/1400 . u will not get noise ^^ . and try hdri very easy .

[Keraressi Abdelkarim]

Your scn should be free ^^ for test . its very good for testing XD . i think with all thos details u will get photorealsitic render from it ^^ .

[Lightman]

Wow thanks Janusz very much for the complement
My rendering times were getting very long , so I reduced the recurse to 4 and that did save a lot of time.
A question I have is on the vegetation. There is a lot of grass and plants that are instanced so I used the Kray surface options in the shader tab on all the vegetation. I have attached an image of my shader settings, Are those good settings to use for vegetation ?
Also I noticed that pathtracing seems to render faster than FG or QMC. Both of them were extremely slow.
The only problem I was having with path tracing was the noise but it looks like if I reduce the recurse to 4 that helps with the noise also.
Is there a way to optimize the scene for QMC or FG that would give me good render times and less noise?

I can release parts of the scene but all the vegetation is from purchased products. Everything else is modeled by me.
The plans for the house though are from a builders site so I don't know if that is ok to give out model from their plans.
Keith